According to ASME B30.9, when using synthetic web slings, a choke angle of less than ____ should not be used without reducing the rated load?

• A. 90
• B. 150
• C. 120
• D. 180

Answer: (C)

The idea being tested is how the choke angle affects the load capacity of synthetic web slings. When two legs of a sling wrap around a load, the angle between those legs—the choke angle—changes how much tension each leg must carry to hold the weight. A tighter choke (smaller angle) concentrates more of the load into each leg, so the sling experiences higher forces than the weight alone would suggest. Because the published rated loads assume a certain choke angle, reducing the angle below that assumption means you must lower the rated load to stay within safe limits.

In ASME B30.9, the threshold is one hundred twenty degrees. If the choke angle is less than that, the rated load should be reduced. If the choke angle is at least one hundred twenty degrees, you can use the published rated load without adjustment. In practical terms, aim to keep the choke angle at or above this threshold; if you can’t achieve that, either choose a sling with a higher capacity or adjust the rigging to share the load more effectively.